DOI: 10.5194/tc-10-977-2016
Scopus记录号: 2-s2.0-84969754486
论文题名: Frozen debris lobe morphology and movement: An overview of eight dynamic features, southern Brooks Range, Alaska
作者: Darrow M ; M ; , Gyswyt N ; L ; , Simpson J ; M ; , Daanen R ; P ; , Hubbard T ; D
刊名: Cryosphere
ISSN: 19940416
出版年: 2016
卷: 10, 期: 3 起始页码: 977
结束页码: 993
语种: 英语
英文关键词: bedrock
; catchment
; embankment
; geological mapping
; geomorphology
; glacial debris
; glacier dynamics
; ice movement
; image analysis
; measurement method
; metasedimentary rock
; metavolcanic rock
; permafrost
; road
; shear band
; slumping
; soil property
; Alaska
; Brooks Range
; United States
英文摘要: Frozen debris lobes (FDLs) are elongated, lobate permafrost features that mostly move through shear in zones near their bases. We present a comprehensive overview of eight FDLs within the Dalton Highway corridor (southern Brooks Range, Alaska), including their catchment geology and rock strengths, lobe soil characteristics, surface movement measurements collected between 2012 and 2015, and analysis of historic and modern imagery from 1955 to 2014. Field mapping and rock strength data indicate that the metasedimentary and metavolcanic bedrock forming the majority of the lobe catchments has very low to medium strength and is heavily fractured, thus easily contributing to FDL formation. The eight investigated FDLs consist of platy rocks typical of their catchments, organic debris, and an ice-poor soil matrix; massive ice, however, is present within FDLs as infiltration ice, concentrated within cracks open to the surface. Exposure of infiltration ice in retrogressive thaw slumps (RTSs) and associated debris flows leads to increased movement and various stages of destabilization, resulting in morphological differences among the lobes. Analysis of historic imagery indicates that movement of the eight investigated FDLs has been asynchronous over the study period, and since 1955, there has been an overall increase in movement rates of the investigated FDLs. The formation of surface features, such as cracks, scarps, and RTSs, suggests that the increased movement rates correlate to general instability, and even at their current distances, FDLs are impacting infrastructure through increased sediment mobilization. FDL-A is the largest of the investigated FDLs. As of August 2015, FDL-A was 39.2 m from the toe of the Dalton Highway embankment. Based on its current distance and rate of movement, we predict that FDL-A will reach the Dalton Highway alignment by 2023. © 2016 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75145
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Department of Mining and Geological Engineering, University of Alaska Fairbanks, Fairbanks, AK, United States; Alaska Division of Geological, Geophysical Surveys, Fairbanks, AK, United States
Recommended Citation:
Darrow M,M,, Gyswyt N,et al. Frozen debris lobe morphology and movement: An overview of eight dynamic features, southern Brooks Range, Alaska[J]. Cryosphere,2016-01-01,10(3)